Scientologie, Wissenschaft von der Beschaffenheit und der Tauglichkeit des Wissens (Scientology: Science of the Constitution and Usefulness of Knowledge) is a 1934 book published by Dr. Anastasius Nordenholz, in which he defines the term "Scientologie" or "Eidologie" as a science of knowing or knowledge and discusses the philosophical implications of the concept.
The book has been cited by some as a possible source of inspiration for L. Ron Hubbard and his better-known conception of Scientology, though this interpretation is disputed

The English-language term "Scientology" originated neither with Hubbard nor Nordenholz, but with philologist Allen Upward, who coined the term in 1907 in his book The New Word.[5] This reference is cited to be a use of the word to ridicule pseudoscientific theories in the book A Piece of Blue Sky by Jon Atack.[6]